Question

Both helium and beryllium have two electrons in the Valence shells. Helium is a noble gas whereas beryllium is a metal, justify... Plzz answer...Urgent

Answer 1

Helium's valence shell can accomodate only 2 electrons. since it os completely filled therefore its a noble gas.
Beryllium's valence shell can accomodate 8 electrons. it is apparent that valenece shell is not filled. and it is also apparent that beryllium will tend to lose its 2 electrons to have the noble gas configuration to form positive ion. since, only metals form positive ions therefore beryllium is a metal.